Apparatus for the fusion electrolysis of metallic chlorides



Aug. 11, 1931. R. SUCHY ETAL 1,818,173

APPARATUS FOR THE FUSION ELECTROLYSIS OF METALLIC CHLORIDES Filed Dec. 15, 1928 Fig-2.

Roger? SuCZZZ/ Xarz SZaiZ Zl/z'l 71 ezmmaschel avwewcow 351 19181 abhor/14W Patented Aug. 11, 1931 UNITED STATES PATENT OFFICE;

ROBERT SUCHY, KARL STAIB, AND WILHELH MOSCHEL, 0F BITTERFELD, GERMANY,

ASSIGNORS TO I. G. FARBENINDUSTRIE AKTIENGESELLSCHAFT, OF ON-THE-MAIN, GERMANY, A CORPORATION OF GERMANY FRANKFORT- APPARATUS FOR THE FUSION ELECTROLYSIS OF METALLIC GHLORDES Application filed December 15, 1928, Serial No.

This invention relates to partitions for separating the electrolytic products in the fusion electrolysis of chlorides, particularly of magnesium.

Hitherto, products of the refractory industry, such as tubes and plates of chamotte, have been suggested as means for se arating the electrolytic products obtaine in the fusion electrolysis of chlorides, particularly of magnesium. These products are, however, liable to undergo more or less rapld destruction, and the costs of frequent restauration may adversely affect the process even to the extent of rendering it uneconomical.

It has been found that the rapid destruction of the chamotte partitions is a purely electrolytic process. The refractory products have a porosity ranging from about 18 to 30 percent, hence they become completely saturated with the electrolyte and are then able to conduct the current, so that the metal resulting from the electrolysis, such as magnesium, is deposited, which reduces the silica.

In accordance with the present invention, the durability of the refractory partitions can be substantially increased by protecting them against the passage of the current by a layer of non-conductive ceramic material of dense structure. Thus, for example, a chamotte plate may be protected against the passage of electric current by facing the same with porcelain plates.

In some cases it, may be desired to dispense with the use of a porous substance,

even only as a base plate, altogether. However, there is a limit to the size of such partitions when employing a dense ceramic material alone, owing to the tendency of large plates to become fractured or to crack due to the stresses set up at the temperature of electrolysis. Obviously these difficulties should be obviated by building up partitions of this character from smaller rectangular elements of a dense ceramic material and fitting them together by means of grooves and tongues. However, when carrying this idea into practice, further difiiculties arise, inasmuch. as the whole structure becomes loos- 326,380, and in Germany December 23, 1927.

ened when exposed to the heat of the electrolysis owing to the thermal dilatation of the bath. This dilatation does not immediately lead to a collapse ofthe partition as a whole; but the interstices formed in consequence "between the structural elements, although but small, sufiice to offer a passage to the current, whereby the destruction of the structure, by chemical reaction, as described above, is initiated.

We have now found that the construction of large partitions of dense ceramic material can notwithstanding be carried into effect in this manner, at the same time avoidin the deficiencies mentioned before, by building up the smaller elements, provided if desired, with tongues and grooves, an fixed together by means of a refractory mortar, in the manner of a straight arch, the elements in this case being wedge-shaped. By this method, the formation of interstices, due to thermal dilation is inhibited, the pressure on the arch mostly caused by its own weight, giving rise to a sagging eflect,'thus keeping upl close contact between the elements of t e structure with the result that the current is debarred from entering into the interior of the partitions. It could not be foreseen that this well known method of construction could find employment in baths for fusion electrolysis for partitions of the kind described.

One form of a partition embodying this principle is illustrated in the accompanying drawings, but the invention is not limited to this example.

In these drawings which form part of this specification Fig. 1 shows in elevation and Fig. 2 in cross section the lateral walls of an electrolytic cell (A), in which a partition wall is inserted (B)' consisting of elements (b) of a dense ceramic material, the latter being fitted together by means of grooves and tongues (C) in the manner of a straight arch.

When, owing to the rise in temperature of the cell during electrolysis, the distance between the lateral walls of the cell is slightly enlarged, the weight of the elements of the partition walk-as well as the weight of any lid or cover resting upon the latter- "coines toibeari upo the stru u e, W1 8? 3 the elements bridging the space between the walls of the cell sag downwards, thus maintaining the rigidity of the structure and close contact of its elements necessary for precluding the current from entering the interstices between said elements.

\Ve claim:

1. In an apparatus for the fusion electrolysis of metallic chlorides, a partition for separating the products of electrolysis comprising a plurality of wedge-shaped plates of non-conductive ceramic material of dense structure, said plates being fitted together so as to form a substantially continuous surface of said partition.

2. In an apparatus for the fusion electrolysis of metallic chlorides. a partition for separating the products of electrolysis comprising a plurality of wedge-shaped plates of non-conductive ceramic material of dense structure, arranged in the manner of an arch and fitted together by a suitable binder, so as to form a substantially continuous surface of said partition.

3. Ill fin apparatus for the fusion electrolysis of metallic chlorides, apartition for separating the products of electrolysis comprising a plurality of wedge-shaped plates of non-conductive ceramic material of dense structure, arranged in the manner of a straight arch, fitted together by means of tongues and grooves and joined together by a refractory mortar, so as to form a substantially continuous surface of said partition.

In testimony whereof we have hereunto set our hands.

ROBERT SUCHY. KARL STAIB. WILHELM MOSCHEL. 

